• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.6
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• pp.627-633
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• 2004

Downlink beamforming is very important in recent mobile communications which requires wireless internet, VOD(Video-On-Demand), multimedia services. This paper addresses and analyzes the essential considerations fur downlink beamforming of smart antenna system to provide wanted characteristics. Major considerations in this paper are HPA power allocation for downlink beamforming, received power at mobile terminal, concept and performance of auxiliary pilot channel, importance and moth of array calibration, and throughput comparison of downlink and uplink. All above mentioned items are investigated in this paper.

• KOREAN POULTRY JOURNAL
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• v.40 no.7
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• pp.129-131
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• 2008

국내에서 발생하고 있는 닭 질병 중에서 심각하게 경제적인 피해를 일으키는 질병들은 주로 온도가 낮은 시기에 집중되어 있다. 하절기에는 몇몇 세균성 질병을 포함하여 고온다습한 환경 조건에 닭이 노출됨으로써 오는 일사와 열사병, 곰팡이 독소 중독증 그리고 가금티푸스를 포함한 몇몇 세균성 질병 등이 주를 이룬다. 그러나 간과해서는 안 될 것은 여름철이라고 해서 환절기와 동절기에 바이러스성 질병의 발생이 없는 것이 아니라 사육환경이 좋아짐으로써 질병의 증상이 잘 드러나지 않고 피해가 나타나지 않을 뿐 각종 질병의 발생이 계속되고 있다는 사실이다. 더위는 털이 많은 닭에게 있어서 분명 견디기 힘든 환경일 것이다. 더위로 인해 겪는 계군의 피해는 사료섭취 감소, 산란저하, 난중감소, 난각질 저하, 부화율 저하, 사료효율의 저하와 스트레스 호르몬의 분비에 의해 성장저하 및 면역시스템에 좋지 않은 영향을 주어서 질병에 대한 감수성이 높아지게 만든다. 계군이 더위를 잘 이기게 해주는 일련의 관리방법들은 계군에 대한 스트레스를 감소 시켜주어 결국은 닭의 면역시스템을 보호해 주는 넓은 의미의 질병 예방 관리라 할 수 있을 것이다. 7월의 폭염을 계군이 효과적으로 이길 수 있게 해 주는 일반적인 관리방법들을 나열해 본다.

• Information and Communications Magazine
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• v.25 no.10
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• pp.42-49
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• 2008

본고에서는 센서네트워크 기술의 역사와 배경 그리고 국방분야에 적용 가능한 센서네트워크 시스템에 대해서 기술한다. 국방 센서네트워크 시스템은 다른 센서네트워크 응용분야에 비해 유선 망 및 이동통신망 시스템에서 요구하는 신뢰성 있는 정보전달, 실시간 지원 등을 요구하고 있으며 또한 다중센서를 복합적으로 이용하여 적의 침입 또는 이벤트 발생을 100% 탐지하고 오보율 낮출 수 있는 기능을 요구한다. 본고에서는 이러한 국방 센서네트워크 시스템에서 요구하는 사항들을 만족시키기 위해 시스템의 주요 구성 요소들에서 수행해야 할 기술들, 센서 신호처리 및 식별 기술, 신뢰성 있는 패킷 전달을 위한 섹터안테나 및 섹터안테나 기반의 MAC 기술 그리고 실시간과 신뢰성 보장을 위한 라우팅 기술에 대해 논의한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.138-140
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• 2012

본 연구에서는 실제 AIS의 정적, 동적 데이터를 수집하여 항계내 통항 선박의 움직임을 파악하였다. 실제 완도항 부근의 직선항로을 통항하는 선박 항적의 분석하여 불규칙적인 선박의 특성을 알아보고자 하였다. 기존의 과거 누적 데이터의 퍼지이론을 활용한 이상 거동의 선박식별 시스템은 전문가 시스템에 의존하여 항적의 비정상성을 판단하므로 항로의 특성에 따른 실 항해상황을 간과할 수 있는 문제점이 있다. 본 연구는 실시간 AIS 정보를 활용하여 항로이탈의 변화율에 해당하는 곡률분석, 항로선으로부터 좌우의 변동을 보다 정확하게 모니터링 할 수 있는 이상 거동 선박을 식별하는 방법을 제안한다. 본 연구는 VTS 및 VMS의 응용서비스로서 해양사고의 사전예방을 위한 연안 및 항만수로의 효율적인 관리에 기여할 것이다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.488-489
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• 2014

본 논문에서는 Z-소스 인버터 (ZSI)의 임피던스 네트워크 내 인덕터 및 커패시터 등 수동소자 수를 감소시키면서 전압 증폭율을 증가시키기 위하여 1개의 스위칭소자를 더 사용하는 스위치 인덕터 구조를 가지는 회로를 제시한다. 이 제시한 회로에서 암단락시간과 첨가된 스위칭소자의 스위칭을 위한 PWM제어방법을 기술한다. 시뮬레이션을 통하여 제시한 스위치 인덕터-스위치 부스터 ZSI의 동작 및 특성의 타당성을 확인한다.

• Journal of Applied Biological Chemistry
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• v.55 no.2
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• pp.109-115
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• 2012

The aim of this study was to determine hepatoprotective effects of pig placenta hydrolysates (PLA) on liver damage-induced rats. Sprague Dawley rats were subcutaneously injected with carbon tetrachlorides and divided into 4 groups: negative control (DMSO treated), two PLA treated groups, low dosage of PLA (LPLA; 300 mg/kg body weight) and high dosage of PLA (HPLA; 1000 mg/kg body weight), and silymarin treated group (80 mg/kg body weight). Rats in each group orally received assigned compounds for 3 weeks. For the normal control group vehicle (corn oil) was injected. After 3 weeks, liver and spleen weights were greater in the two PLA and silymarin groups than the negative control group. After bromosulfalein (BSP) treatment, the clearance rates were in the descending order of negative control > LPLA > HPLA = silymarin and serum BSP levels exhibited the opposite trends of the clearance rates. Serum levels of aspartate aminotransferase, alanine aminotransferase, triglyceride, and cholesterol lowered with PLA in a dose-dependent manner. The decrease with HPLA was similar to that with silymarin. In addition, triglyceride, cholesterol, lipid peroxides levels in the liver decreased in HPLA and silymarin compared to the negative control. The liver morphometry was improved in HPLA- or silymarin-treated rats in comparison to the negative control. In conclusion, HPLA administration ameliorated the hepatotoxicity as much as silymarin in rats injected with carbon tetrachlorides.

• Korean Journal of Environmental Agriculture
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• v.15 no.1
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• pp.70-76
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• 1996

Absorption, distribution, excretion and metabolism of $^{14}C-{\alpha}-Endosulfan$[1,4,5,6,7,7-hexachloro-8,9,10-=trinorborn-5-en 2,3-ylenebismethylene]sulfite) were studied in male mouse(Balb/c) after single intraperitoneal treatment as the dose level of 7.5 mg/kg body weights. After treatment of $^{14}C-{\alpha}-endosulfan$, the radioactivity was rapidly excreted into the urine(63.9 %) within 4 days, thereafter the excretion ratio was constant. Radioactivity levels in the tissues was reached maximum 0.5 hr in heart, 2 hrs in liver and kidney after the treatment, then decreased with time. Endosulfan was metabolized to ${\beta}-endosulfan({\beta}-E)$, endosulfan ether(EE), endosulfan sulfate(ES), and endosulfan alcohol(EA). The main metabolites were EA(13.25 %) in liver and endosulfan hydroxyether(EHE)(19.37 %) in kidney. The urinary metabolites were EA(43.21 %), ES(4.78 %), ${\beta}-E$(7.21 %), EE(3.72 %) and EHE(18.04 %).

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.25-30
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• 1997

Absorption, distribution, metabolism and excretion of $^{14}C-carbofuran$(2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamte) were studied in carp(Cyprinus carpio L.) after the treatment of carbofuran at the dose level of 43 parts per billion. Maximum radioactivities in tissues(liver, kidney, gut, gall bladder) and blood of carp were shown 12hrs after the treatment of $^{14}C-carbofuran$. Carbofuran was metabolized to 3-hydroxycarbofuran and 3-ketocarbofuran in liver and kindney of carp, and the major metabolite was 3-hydroxycarbofuran. Most radioactivity absorbed into the carp tissues was eliminated 3hrs after transfer of the carp to fresh water. The excretory metabolites were 3-ketocarbofuran(32.3%), 3-hydroxycarbofuran(52.8%) and an unknown metabolite(2.6%) during the period of 3hrs of the excretory experiment.

• Journal of Nutrition and Health
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• v.3 no.3
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• pp.167-178
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• 1970

Elucidation of the metabolic pathway due to 50% dietary restriction carried out in this study. Seventy male and female wealning rats, weighed $43{\pm}2g$ were divided into seven groups, 10 rats each. Twenty rats, ten males and ten females were sacrificed every three weeks after 50% dietary restriction for whole length of the experiment, nine weeks. Pair-feeding was employed in this study. According to the increment of the dietary restricted period, the body and organ weights were decreased. Especially liver and spleen were mostly shrinked in their weights, and brain was the most stable organ in account of dietary restricted effect. In comparison nitrogen retention between restricted and unrestricted groups, the former showed lower than the later but tubulated into the rate of Nitrogen retention per gram of body weight, reverse was true in this respect. In regardness of the experimental organs, spleen revealed the most fast change and the brain the most slow change their content of RNA and DNA in account of the 30% dietary restriction. Hematological investigation did not show any anemic conditions in both restricted and unrestricted groups. Also serum albumin contents A/G ratio, did not effect due to 50% dietary restrictions.

• Nuclear Engineering and Technology
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• v.4 no.4
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• pp.301-305
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• 1972

The polymerization rates of monomer or monomer mixture impregnated with catalyst into domestic soft woods such as pinus densiflora, pinus rigida and poplus deltoides e. t. c. were measured. The results were compared with those obtained by radiation curing method and the following conclusions were derived ; (1) Pinus densiflora and pinus rigida are superior to the poplus deltoides, and methyl methacrylate(M. M. A. ) is more effective than other monomers as far as the polymerization rates are only taken into account. (2) The polymerization rate of vinyl acetate is generally slow. And the polymerization rate of the monomer is the slowest in case of being impregnated into poplus deltoides. However, the polymerization rate of the comonomer composed of vinylacetate and M. M. A. is the fastest among the other monomers or monomer mixtures in woods regardless of the curing method. (3) The general trend of polymerization of monomer in wood is similar to that of monomers themselves in both curing methods if the woods contain not much resin.